Control



March 20, 1934. w. DOBLE 1,951,351

CONTROL Filed March 23, 1931 IF 'IIE- J- 7////lllllllllllill/lill;

:I j INVENTOR. #Varna/7 ob/e A TTOR Milam Patented Mar. 20, 1934 UNITED sTATEs PATENT GFFICE 7 Claims.

My control relates primarily to means for regulating the operation of vapor generators and more particularly to mechanism for use in conjunction With steam boilers to ensure a proper I supply of feed water or other liquid being sup-vv plied to the boiler. In a particular type of boiler in which. my invention is especially applicable the proper introduction of water is a very diiiicult operation inasmuch as the supply is intended to be closely correlated with the supply of heat. Particularly in automotive use the difficulty of supplying water is great inasmuch as the load on the boiler is continually fluctuating and the supply of Water must be coordinated therewith.

An object of my invention is to provide a control Which affords an accurate supply of feed fluid for a boiler.

Another object of my invention is to provide a control system which responds quickly to the controlling factors.

Another object of my invention is to provide an independent water supply for a boiler.

The foregoing and other objects are attained in the embodiment of the invention shown in the drawing, in which Figure 1 is a diagram of the control of my invention, portions of the mechanism being shown in cross section.

Figure 2 is a fragmentary section of a modified $0 form of the chamber shown in Figure 1.

In its preferred form, the control of my invention comprises means for establishing a differential pressure in a conduit carrying feed liquid to a boiler together with means effected by the 36 differential pressure for energizing an electrical circuit which in turn controls the establishing means.

Although the invention may be embodied in a plurality of widely variant forms I have chosen to illustrate itas it is included in a system primarily designed for use in automotive vehicles such as trucks, automobiles, airplanes, boats and the like. In this form of the invention, there is provided a boiler, generally designated 6, includ-l ing a casing 7 which contains a boiler coil 8. The boiler coil 8 usually comprises along tube wound upon itself and through which the water is forced to flow in a predetermined path. Such a boiler is aptly termed a forced circulation boiler. Water I0 which is introduced into the foot of the boiler, as at 9, flows through the various convolutions thereof and is heated by products of combustion within the casing 'l from any suitable source thereof, not shown. The heated liquid gradually is converted into vapor which can be discharged vfrom the outlet l1 of the boiler under control of a throttle valve l2.

Due to the various positions in which the valve 12 may be located the amount of Vapor or steam discharged from the boiler 6 varies considerably 60 and the pressure of the contents of the boiler also varieswithin wide limits.

In order to supply a suitable liquid, usually Water, to the boiler I preferably afford a liquid pump, generally designated 13, comprising a water pump 0I cylinder 14 and a steam cylinder 16. The Water pump 14 withdraws Water through a conduit 1'? from a storage tank 18 and discharges the pumped water into a conduit 21 extending to the foot of the boiler 9. In order to insure a relative- Y0 ly constant or regulated supply of feed liquid to the boiler through the conduit 21 I preferably interpose in the conduit a body 22 within which is a channel 23 forming a portion of the conduit 21 and which intermediate its ends is provided with 'l a restricted orice 24. Formed in the body 22 is a chamber 26 which at opposite ends communicates by channels 27 and 28 with opposite sides of the orifice 24.

When liquid is pumped by the pump 14 l0 through the conduit 21 the pressures existing on opposite sides of the orifice 24 are communicated through the channels 27 and 28 to opposite ends of the chamber 26. In' order to utilize the pressures so established I provide within the chamber 0l 26 a freely reciprocable piston 29 which is urged toward one end of the chamber 26 by a spring 31 or other biasing means. Thus, if an excessive pressure exists in the channel 28 the piston 29 is moved against the urgency of the spring 31 While 90 if a deficient pressure exists in the channel 28 the spring 3l urges the piston toward the channel 28.

Since the rate at which heat is imparted to the tube 8 in the boiler 6 may vary and since the rate of flow through the orifice 24 is substantially 95 constant I preferably provide means for varying the flow through the orifice 24 by varying the effectiveI area through the orifice. To this end `there is inserted in the casing '7 a rapidly expanding jacket 32 whichA is in thermal contact either 10| with the tube 8, with the contents of the tube, with the products of combustion within the casing 7 or any suitable medium. Within the rapidly expanding tube 32 and affixed to the far end thereof is a substantially non-expanding rod 33 105 which extendsrthrough a stuiiing box 34 in the body 22 and is tapered on the end, as at 36, to seat in and, when seated, entirely close the orifice 24. Due to the high co-eiiicient of expansion of :the jacket 32, an increase in temperature within `the 110 casing 7 causes the rod 33 to be withdrawn from seated position in the orifice24 and to allow an increased ilow therethrough. Since the movement of the rod 33 is substantially in accordance with a fluctuation in temperature the amount of water flowing through the body 22 is in proportion to the heat liberated within the boiler 6. 1

In order to maintain the desired now through the orice 24 despite variations in size of the orifice, I preferably afford means for controlling the operation of the pump 13. To this end the steam cylinder 16 of the pump 13, which is in driving relationship with the water pump cylinder 14, is supplied with steam through a duct 41 extending from the boiler outlet 11 through a valve 42 to the steam cylinder 16. The valve 42 is preferably of the type shown in the copending application of Warren Doble Serial No. 524,667 filed March 23, 1931, entitled Valve and which discloses in general a valve for controlling the ilow through a duct under the inuence of an electrically energized solenoid such as 43. When the valve 42 is opened to permit4 flow through the duct 41 the steam cylinder 16 operates the water pump 14 and withdraws water from the source 18 and discharges it through the conduit 21 into the foot of the boiler 9. When the valve 42 is closed there is no steam ow through thecluct 41, the steam cylinder 16 does not operate and no water is withdrawn from tank 18 nor pumped into the boiler inlet 9.

To energize the solenoid 43 which controls valve 42 and to render the pump 14, which may be considered as a differential pressure producing means, responsive to the differential pressure existing on opposite sides of the orifice 24, I utilize the movement of piston 29. To this end there is supported in one end of the chamber 26 a contact 44 which is insulated, as at 4 6, from the material of the body 22 which usually is metal. The contact 44 forms part of an electrical circuit which can be traced from a source of electrometive force, such as a battery 47, one side of which is connected to a ground 48 and the other side of which extends through a main switch 49, the solenoid 43 and a conductor 51 to the contact 44.

The circuit is'there interrupted unless, by virtue of a deficiency of pressure in the passage 28, the spring 31 forces the piston 29 to abut the contact 44. In this event the circuit is completed from the contact 44 through the piston 29, the spring 31 and the metallic body 22 to a grounded return 52. When the circuit is closed by the piston 29 being in abutment with contact 44, the

that no matter what the effective area of orifice solenoid 43 is energized, the valve 42 is` opened and steam flows from the boiler to the steam cylinder 16 so that the pump 14 is operated to force Water through the orifice 24 and into the boiler coil 8. Any excessive pressure in the passage 28 causes the piston 29'to travel away from contact 44 so that the circuit to the solenoid 43 is broken and the pump 14 is stopped.

In operation the piston 29 abuts the contact 44 to complete the circuitvand rises therefrom to break the circuit in an intermittent manner so 24,the pump 14 always pumps the proper amount of water to maintain the differential pressure and to supply the boiler 6.

In Figure 2 there is disclosed the lower end of a chambery 56 in most respects comparable to the chamber 26 but in which a standard spark plug 57 is utilized. to provide a contact 58 equivalent to the contact 44, and which isconnected in circuit by a lead 59 corresponding to the lead 51.

In practice it is found that with the arrangement described the flow of Water to the boiler is as desired and. is carefully regulated, controlled `spect to the control of the mechanism but this effect leads to a remarkable economy in pump operation, since the fluid expanding in the fluid cylinder 16 after the valve 42 has been closed does Work' expansively on the pump 14.

As soon, however, as the expanding fluid in the cylinder 16 has expended its force, no additional flow from the pump 14 takes place and thepiston 29 again abuts contact 44 thereby reestablishing a ow of steam from the boiler through the valve 42 to the engine 16 and again causing the pump to force water through the conduit 21. The increase in vdiiferential pressure, due to such ilow then breaks the circuit again and the remaining steam in the cylinder 16 works expansively as before. This is equivalent to operating the engine 16 with a steam cut-off at relatively short stroke which affords very economic y'operation even withv a single cylinder unit.

\ Thus, this system is especially advantageous in obtaining in effect'a cut-oil' Without the usual 'disadvantages thereof, since with an ordinary single cylinder engine operating at say fifty per- 110 cent cut-off, special starting mechanism must be provided because the engine may stop at random in the latter portion of its stroke and the valve, being set for fifty percent cut-off, vis not open to re-admit steam. In the present instance, no matter where the pump 14 is stopped or Where the cylinder 16 stops, whenever there is no flow from the pump 14 the piston 29 is in abutment with the contact 44 so that steam flow is re-established as valve 43 is opened and the pumping 120 mechanism is self starting in any position of its cycle. f It is to be understood that I-do not limitmyself to the form of control shown and described herein, as the invention, as set vforth imthe following claims may be embodied in a plurality of forms.

I claim: e

1. A control comprising a grounded chamber, a contact in said chamber and insulated therefrom, av piston in said chamber, a spring electrically connected to said chamber for biasingv said piston to abut said "contact, a pump for forcing liquid into said chamber to drive said piston from said contact, electrical means for controlling'said' pump, a grounded source of electro-motive force, and means for connecting said source, said electrical means and said contact inseries.

2. A control comprising a body having a restricted'orice therein, a pump for forcing liquid through said orifice, a chamber, a piston in said chamber adapted to move in accordance with differential pressures vexisting on opposite sides of 'said orifice, electrical means for controlling said pump, and an electrical circuit closed by said piston for energizing said electrical means.-

3. A control comprising a body having therein a restricted orifice and a chamber 1communicating at opposite ends with opposite sides of' said orifice, an electric contact projecting into said chamber and insmated from said body, a pistonlo in said chamber movable into and out of abutment with said contact in response to differential pressures existing on opposite sides of said orice, a pump for forcing liquid through said orifice, an electrically operated valve for controlling saidpump, and an electrical circuit including said valve, said piston and said contact.

A4.' A control comprising a boiler, a water pump, a conduit for conducting water from said pump to said boiler, said conduit having a restricted orifice therein, a piston adapted .to move in re-. spouse to differential pressures on opposite sides of said orice, a steam engine for driving said pump, a duct for conducting steam from said boiler to said engine, an electrically actuated valve for controlling flow through said duct, and

Q an electric circuit including said valve and said said pump, an electrically actuated valve for controlling the supply of fluidto said engine, switch members submerged in said liquid for making or breaking the electric circuit for said valve,v and a movable abutment on opposite sides-,subject to diierential pressures on opposite sidelsjdo;

orice and thus responsive to liquid'ow through said orice for actuating one of said switch members.

7. A control comprising a conduit having anorifice therein, an electric circuit, a p ump operating in accordance'with the condition of said electric circuit for forcing liquid through said conduit, switch members submerged in said liquid for controlling said circuit, and means responsive to differential pressures on opposite sides of said orice for relating said contacts to condition said circuit. l

WARREN DOBLE.4

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